Located deep within the pelvic region, the iliopsoas muscle spans between the hip bone and femur, serving a variety of functions for the hip joint. This article will discuss the anatomy and functions of this muscle.
|Insertion||Lesser trochanter of the femur (via shared tendon with psoas major)|
|Functions||Together with psoas major: Flexion and external rotation of the thigh;|
|Psoas major muscle|
|Origin||Transverse processes of lumbar vertebrae L1-L5;
Bodies of T12-L5 and their intervertebral discs.
|Insertion||Lesser trochanter of the femur (via shared tendon with iliacus)|
|Innervation||Anterior rami of lumbar spinal nerves L1-L3|
|Functions||Together with iliacus: Flexion and external rotation of the thigh;
Contracting alone: Lateral flexion of the trunk
Origin and Insertion
The psoas major and iliacus muscles have distinct origins but share a joint insertion. The iliacus muscle originates from the iliac fossa and iliac crest. The psoas major originates from the transverse processes of lumbar vertebrae L1-L5 and some adjacent structures, including the bodies of T12-L5 vertebrae and the intervertebral discs between them.
Both muscles converge towards the femur, and via a shared tendon, they insert onto the lesser trochanter of the femur.
The two components of the iliopsoas muscle have different innervations:
- Psoas major is innervated by the anterior rami of lumbar spinal nerves L1-L3
- Iliacus is innervated by the femoral nerve
Solidify your knowledge of the anatomy of the back muscles with more in-depth articles.
The iliopsoas muscle is the primary and . When the insertion is the fixed point, the psoas major contributes to the flexion of the trunk during bilateral contraction (contraction from both sides). When only one psoas major contracts in this manner (unilateral contraction), it aids in the lateral flexion of the trunk.
Muscles That Act On The Anterior Thigh (From The Hip)
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